(0643) Extent of Resection of Mucoepidermoid Carcinoma Involving the Facial Nerve

Introduction: The purpose of this study was to compare the oncologic and functional outcomes of different intraoperative facial nerve management strategies in patients with mucoepidermoid carcinoma (MEC) and normal preoperative facial nerve function.

Methods: A retrospective study of patients undergoing surgical treatment for MEC from January 1, 2006-December 31, 2022. Inclusion criteria included diagnosis of MEC, normal preoperative facial nerve function, and intraoperative evidence of tumor abutment or encasement of the facial nerve.

Results: In total, 17 patients were included. Of them, 7 underwent facial nerve resection and had pathological evidence of facial nerve invasion, 6 underwent nerve resection because of encasement of the nerve but did not have evidence of microscopic facial nerve invasion on pathology, and 4 had intraoperative evidence of tumor encasement of the facial nerve but did not undergo resection. Perineural invasion was more common in those who underwent microscopic evidence of facial nerve invasion (n = 7, 100%). Patients who did not undergo resection despite intraoperative evidence of tumor encasement underwent nerve biopsy, and 2 had evidence of perineural invasion. All patients who did not undergo facial nerve resection underwent adjuvant radiation compared to 67% of patients who had nerve resection. Extensive reconstruction was required for patients who underwent nerve resection compared to those who did not. Median follow up was 55 months with no recurrence. All patients who did not undergo nerve resection had normal facial nerve function at last follow up compared to 38% of patients who underwent facial nerve function.

Conclusions: Preservation of the facial nerve and adjuvant radiation therapy in MEC is associated with excellent tumor control and superior immediate and long-term facial nerve function.